Rajasthan Board RBSE Class 10 Science Solutions Chapter 2 Human System

Textbook Questions Solved

I. Multiple Choice Questions

Question 1:
Which of the following controls the movement of food, digested food and waste materials?
(a) Sphincters
(b) Mucosa
(c) Submucus Layer
(d) Both ‘b’ and ‘c’
Answer:
(a) Sphincters

Question 2:
Which type of teeth is most prominent in carnivorous animals?
(a) Incisor
(b) Canine
(c) Premolar
(d) Molar
Answer:
(c) Canine

Question 3:
What is the main function of epiglottis?
(a) To send food in pharynx
(b) Prevent food from going into windpipe
(c) To send food into oesophagus
(d) None of the above
Answer:
(b) Prevent food from going into windpipe

Question 4:
Majority of digestion by enzymes takes place in which part of alimentary canal?
(a) Duodenum
(b) Ileum
(c) Qesophagus
(d) Large intestine
Answer:
(a) Duodenum

Question 5:
Which of the following is not a salivary gland?
(a) Parotid
(b) Sublingual
(c) Madibular
(d) Pituitary gland
Answer:
(d) Pituitary gland

Question 6:
Which enzyme is not secreted by pancreas?
(a) Amylase
(b) Trypsin
(C) Rennin
(d) Lipase
Answer:
(c) Rennin

Question 7:
Which of the following is a secondary respiratory organ?
(a) Mouth
(b) Nose
(c) Nasopharvnx
(d) Trachea
Answer:
(a) Mouth

Question 8:
How many lobes are present in the left lung?
(a)3
(b)4
(c)2
(d) 1
Answer:
(c)2

Question 9:
Which of the following is present in alveoli?
(a) Stratified epithelium
(b) Epithelium
(c) Cartilaginous rings
(d) None of these
Answer:
(b) Epithelium

Question 10:
What is the name of the liquid portion of blood?
(a) Serum
(b) Lymph
(c) Plasma
(d) None of these
Answer:
(c) Plasma

Question 11:
Red Blood Cells are produced by which of the following?
(a) Spleen
(b) Bone marrow
(c) Lymph nodes
(d) None of these
Answer:
(b) Bone marrow

Question 12:
Which of the following is not a white blood cell?
(a) B-lymphocyte
(b) Platelet
(c) Basophil
(d) Monocyte
Answer:
(b) Platelet

Question 13:
RBCs of which blood group has both A and B antigens?
(a) O
(b) A
(c) B
(d) AB
Answer:
(d) AB

Question 14:
Blood crosses through heart how many times during a cardiac cycle?
(a) One
(b) Three
(c) Two
(d) Four
Answer:
(c) Two

Question 15:
What is the main excretory product in humans?
(a) Ammonia
(b) Uric acid
(c) Urea
(d) Both ‘a’ and ‘c’
Answer:
(c) Urea

Question 16:
Glomerulus is present in which of the following?
(a) Bowman’s capsule
(b) Renal tubules
(c) Loop of Henle
(d) None of these
Answer:
(a) Bowman’s capsule

Question 17:
Which is the main male sex hormone in humans?
(a) Estrogen
(b) Progesterone
(c) Testosterone
(d) Both ‘b’ and ‘c’
Answer:
(c) Testosterone

Question 18:
Which of the following is the primary sex organ?
(a) Scrotum
(b) Ovary
(c) Testis
(d) Both ‘b’ and ‘c’
Answer:
(d) Both ‘b’ and ‘C’

Question 19:
Motor neurons carry signals
(a) From central nervous system to organs
(b) From organs to central nervous system
(e) Both ‘a’ and ‘b’ are correct
(d) Both ‘a’ and ‘b’ are incorrect
Answer:
(a) From central nervous system to organs

Question 20:
Corpora quadrigemina is present in
(a) Forebrain
(b) Hindbrain
(e) Midbrain
(d) Both ‘a’ and ‘b’
Answer:
(c) Midbrain

Question 21:
Which of the following hormones is not secreted by pituitary gland?
(a) Growth hormone
(b) Vasopressin
(c) Melatomn
(d) Prolactin
Answer:
(c) Melatonin

Question 22:
Which of the following is responsible for regulation of circadian variations?
(a) Thyroid gland
(b) Pancreas
(c) Adrenal gland
(d) Pineal gland
Answer:
(d) Pineal gland

Human System Very Short Answer Type Questions

Question 23:
Name the fundamental structural and functional unit of body.
Answer:
Cell

Question 24:
Define the digestive system.
Answer:
The system which converts the components of food into simple and absorbable substances is called digestive system.

Question 25:
What is the function of sphincters?
Answer:
Sphincters control the movement of food through alimentary canal and prevent backflow of food.

Question 26:
Name the glands associated with digestive system.
Answer:
Salivary glands, pancreas and liver

Question 27:
What is the function of incisor teeth?
Answer:
Incisor teeth are meant for cutting.

Question 28:
The stomach has how many parts?
Answer:
The stomach has three parts, viz. cardiac, fundus and pylorus.

Question 29:
Most of the digested food is absorbed in which part of alimentary canal?
Answer:
Absorption of digested food primarily happens in jejunum which is the middle part of small intestine.

Question 30:
Which is the largest gland in human body?
Answer:
Liver

Question 31:
The enzyme ptyalin is secreted by which gland?
Answer:
Salivary gland

Question 32:
The voice box contains how many cartilages?
Answer:
Nine

Question 33:
The mucus in trachea is produced by which part?
Answer:
Epithelium

Question 34:
How much blood is present in the body of a normal adult?
Answer:
5 litre

Question 35:
What is the life span of platelets?
Answer:
10 days

Question 36:
What is the name of blood vessels which carry deoxygenated blood?
Answer:
Vein

Question 37:
What is pericardium?
Answer:
The double membranous covering around the heart is called pericardium.

Question 38:
What is the function of major vein?
Answer:
The major vein brings blood from systemic veins to heart.

Question 39:
The process of excretion of ammonia is known by which name?
Answer:
Ammonotelic

Question 40:
Which is the main excretory organ in humans?
Answer:
Kidneys

Question 41:
Ova are produced by which organ?
Answer:
Ovary

Question 42:
Which is the main sex hormone in women?
Answer:
Estrogen

Question 43:
Where does implantation of placenta take place in mother?
Answer:
Endometrium

Question 44:
Which system is responsible for coordination among various organs?
Answer:
Nervous system and Endocrine system

Question 45:
Grey matter is present in which organ?
Answer:
Brain

Question 46:
Write the name of a neurotransmitter.
Answer:
Acetylcholine

Question 47:
Which hormone is produced by thyroid gland?
Answer:
Thyroxin

Question 48:
Adrenalin hormone is secreted by which gland?
Answer:
Ans. Adrenal gland

Human System Short Answer Type Questions

Question 49:
Name the organs which are involved in digestion.
Answer:
Following organs are involved in digestion: Mouth, stomach, small intestine, salivary glands, pancreas and liver.

Question 50:
Briefly explain the structure and function of stomach.
Answer:
This is a J-shaped structure which lies between oesophagus and duodenum. The stomach lies towards left in the abdominal cavity and just behind the diaphragm. This is a flexible organ which can accommodate up to three litres of food. Stomach can be divided into three parts, viz. cardia, fundus and pylorus.
Functions of stomach are as follows:

  • Churning the food into fine paste.
  • Killing any germs in food.
  • Partial digestion of food.

Question 51:
What is the location of salivary glands? Explain its structure.
Answer:
Salivary gland is situated in the buccal cavity. There are three types of salivary glands, viz. parotid, submandibular and sublingual. Parotid glands are situated near cheeks. Submandibular glands are situated near jaws. Sublingual gland is situated below tongue. Salivary gland is composed of glandular epithelium and is exocrine in function.

Question 52:
Comment on main functions of nose.
Answer:
Functions of nose:

  • Provides passage to air.
  • Traps dust particles from air.
  • Moistens the air entering the respiratory system.
  • Gives sense of smell.

Question 53:
How does pharynx help in respiration?
Answer:
Pharynx in humans, is the part of digestive system and the conducting zone of respiratory system. Pharynx constitues nasopharynx, oropharynx and laryngopharynx. The role it plays in respiration is that it allows the air passage from nasal chamber to oropharynx via nasopharynx.

Question 54:
What is the importance of respiratory muscles?
Answer:
Respiratory muscles play important role in respiration. The diaphragm contracts to create negative pressure inside lungs. This facilitates entry of air from outside. Intercostalis muscles also play important role in breathing. These muscles are attached between the ribs and are important in manipulating the width of the rib cage.

Question 55:
What is blood? What are the functions of blood?
Answer:
Blood is a fluid connective tissue which transports various substances in the body. Following are the functions of blood:

  • Exchange of oxygen and carbon dioxide.
  • Transport of nutrients.
  • Transport of medicines.
  • Maintenance of pH in body.
  • Facilitates immunity.
  • Controlling the temperature of body.
  • Transportation of hormones to target sites.
  • Removal of metabolic wastes.

Question 56:
What is the role of blood vessels in circulation of blood?
Answer:
Following are the role of blood vessels in circulation of blood:

  • Veins usually carry deoxygenated blood.
  • All the veins carry blood from different organs to heart.
  • Arteries usually carry oxygenated blood.
  • All the arteries carry blood from heart to different organs.
  • Capillaries supply blood up to the tissue level.

Question 57:
Explain the structure of kidney.
Answer:
Kidney resembles like kidney beans and is dark brown in colour. There is a constriction in the middle and it is called hilum. There is a funnel shaped pelvis on the inner side of hilum. The outer part of kidney is called cortex and the inner part is called medulla. Each kidney has numerous filtering units called nephrons.

Question 58:
Explain the organs involved in excretion, other than kidney.
Answer:
Other organs involved in excretion are as follows:
Lungs: Carbon dioxide is removed through lungs.
Skin: Some excretory products are removed from skin along with sweat.
Mouth: Some waste products are removed from mouth along with spit.

Question 59:
What are the functions of the primary sex organ in women?
Answer:
Functions of the primary sex organ in women are as follows:

  • Production of eggs.
  • Production of hormones, estrogen and progesterone.

Question 60:
What is the role of vas deferens?
Answer:
Vas deferens is a tube-like structure coming out of testis. It provides passage to sperm.

Question 61:
What is the importance of spinal cord?
Answer:
Spinal cord controls various voluntary actions. Spinal cord provides a passage to nerve signals from brain to different organs and vice versa.

Question 62:
Explain the structure and functions of forebrain.
Answer:
Forebrain is composed of cerebrum, thalamus and hypothalamus. Cerebrum is surrounded by thalamus. The hypothalamus is near diencephalon which is at the base of cerebrum. Following are the functions of forebrain:

  • Control of motor functions.
  • Perception of different senses.
  • This is the centre of thinking, intelligence, language, etc.
  • Hypothalamus gives sense of hunger and thirst.

Question 63:
What is the role of hypothalamus in endocrine system?
Answer:
Hypothalamus controls the release of hormones from pituitary gland. Hypothalamus secretes two types of hormones, viz. releasing hormone and inhibitory hormone. Releasing hormone facilitates secretion of hormones from pituitary gland. Inhibiting hormone prevents the secretion of hormone from pituitary gland.

Question 64:
Explain the endocrine and exocrine functions of pancreas.
Answer:
Endocrine functions of pancreas: It secretes insulin and glucagon which play a role in metabolism of sugar.
Exocrine functions of pancreas: It secretes many enzymes like amylase, trypsin, chymotrypsin, lipase, etc. to break down the carbohydrates, proteins and fats in the food.

Human System Long Answer Type Questions

Question 65:
Explain the human digestive system. Explain the significance of enzymes which are involved in digestion.
Answer:
The digestive system is composed of an alimentary canal, some accessory glands and organs. The alimentary canal begins from mouth and ends up in anus. The alimentary canal is 8 – 10 m in length and is also called the digestive canal.

Mouth: The opening of the alimentary canal leads to buccal cavity or mouth which is a bowl-shaped structure. Buccal cavity is lined by soft palate at bottom and hard palate at top. Pharynx: The buccal cavity opens in a funnel-shaped cavity called pharynx. Through the pharynx, the food goes to oesophagus and air goes to the windpipe. Both the pipes open near the lower surface of pharynx, windpipe is in front while food pipe is at back.

Oesophagus: This is a narrow tube which goes from pharynx to stomach. Oesophagus is 25 cm in length. The main function of oesophagus is to carry food from mouth to stomach. There is a cartilaginous flap called epiglottis which ensures that the food goes only to the food pipe and does not go to the windpipe. Secretions of mucus glands in oesophagus make the food slippery. Different parts of oesophagus alternately contract and relax. This movement is called peristalsis and is responsible for forward movement of food.

Stomach: This is a J-shaped structure which lies between oesophagus and duodenum. The stomach lies towards left in the abdominal cavity and just behind the diaphragm. This is a flexible organ which can accommodate up to three litre of food.

Small Intestine: This is a highly coiled tube-like structure which begins from pylorus and ends in large intestine. Small intestine is about 7 m long. This is the most important part of the alimentary canal as major portion of digestion takes place in small intestine. The small intestine can be divided into three portions, viz. duodenum, jejunum and ileum.

Large Intestine: This is much shorter than small intestine and has a larger diameter. Some microbes live in large intestine. These microbes digest the remaining food by fermentation. Moreover, excess water and salt are absorbed by the walls of large intestine.

The significance of Enzymes: Many enzymes are produced in digestive system. These are hydrolytic enzymes. They convert components of food into simpler substances so that they can be easily absorbed.

Question 66:
Explain the significance of trachea, bronchioles, lungs and respiratory muscles in human respiratory system.
Answer:
Trachea: Trachea is composed of cartilaginous rings. This prevents trachea from collapsing and keeps it always open for passage of air.
Bronchioles: Bronchioles take the air to two lungs.
Lungs: Lungs are highly flexible in nature. They can expand to accommodate a large amount of air.
Respiratory Muscles: Diaphragm and intercostalis muscles are the respiratory muscles. These muscles create negative pressure inside lungs to facilitate movement of air from atmosphere. These muscles also facilitate removal of air from lungs.

Question 67:
What is blood? Explain various components of blood. Explain the importance of blood.
Answer:
Blood is a fluid connective tissue. There are two parts in blood, viz. plasma and formed
elements.
Plasma: Plasma composes about 55% of total blood. About 92% of plasma is composed of water and rest is composed of organic and inorganic substances.
Formed elements are composed of cells which are as follows:

Red Blood Cells or Red Blood Corpuscles (RBCs): RBCs comprise 99% of blood cells. RBCs contain a protein called haemoglobin which imparts red colour to them. They lack nucleus. The life of RBCs is 120 days.
White Blood Cells or White Blood Corpuscles (WBCs): These are colourless as haemoglobin is absent in them. They provide immunity to the body and fight against diseases. WBCs are produced in bone marrow. There are two types of WBCs, viz. granulocytes and agranulocytes.

  • Granulocytes: Neutrophil, eosinophil and basophil are the granulocytes. Neutrophils are largest in number.
  • Agranulocytes: Lymphocytes and monocytes are the agranulocytes. Lymphocytes are of three types, viz. B-lymphocytes, T-lymphocytes and natural killer cells. Lymphocytes provide immunity against diseases. Monocyte becomes macrophage after attaining maturity. Neutrophil, lymphocyte and macrophage are the prime defenders and eat away antigens.

Platelets: They are also known as thrombocytes. There are about 3 lakh platelets per cubic mm of blood. The lifespan of platelets is of 10 days. Platelets facilitate clotting of blood.
Importance of Blood:

  • Blood transports different substances in the body.
  • It controls the temperature of body.
  • It maintains pH of body.
  • It plays an important role in immunity

Question 68:
Analyse urine formation in humans. Explain the structure of kidneys.
Answer:
Urine formation takes place in three steps, viz. glomerular filtration, reabsorption and collection.

  • Glomerular Filtration: The tuft of capillaries inside bowman’s capsule is called glomerulus. It is connected with two types of arterioles. Afferent arteriole take blood to glomerulus and efferent arteriole take blood away from glomerulus. The lumen of efferent arteriole is less than that of afferent arteriole. This creates high pressure inside glomerulus and thus blood is filtered under high pressure. Glucose, amino acid, urea, etc. are filtered from blood and sent to bowman’s capsule.
  • Reabsorption: The glomerular filtrate contains high quantity of water. This water is reabsorbed as glomerular filtrate passes through convoluted tubules. Some salts are also reabsorbed. Reabsorption helps in reducing the volume of urine.
  • Collection: After reabsorption, urine is formed. It passes through collecting duct and finally is stored in urinary bladder.
  • Structure of Kidney: Kidney resembles like kidney beans and is dark brown in colour. There is a constriction in the middle and it is called hilum. There is a funnel shaped pelvis on the inner side of hilum. The outer part of kidney is called cortex and the inner part is called medulla. Each kidney has numerous filtering units called nephrons.

Question 69:
Make a diagram of male reproductive system and explain the function of primary reproductive organs in humans.
Answer:
The primary reproductive organs in males are testis, vas deferens, seminal vesicles and prostate gland.
Testis produce sperms. Vas deferens provides a channel for sperm to seminal vesicles. Secretion of prostate gland goes to seminal vesicle where semen is formed.

The primary reproductive organs in females are ovaries, fallopian tubes, uterus and vagina. Ovaries produce eggs, fallopian tubes receive an egg during ovulation. Fertilization takes place in fallopian tube. Uterus is the site of implantation and development of embryo. Vagina provides the passage to semen and serves as birth canal.

Question 70:
Explain the nervous system with the help of a suitable diagram. Explain the importance of hypothalamus and pituitary gland.
Answer:
The nervous system can be divided into two parts, viz. central nervous system and peripheral nervous system.

Central Nervous System: This is composed of the brain and spinal cord. The brain can be divided into three main parts, viz. forebrain, midbrain and hindbrain.
Peripheral Nervous System: This is composed of peripheral nerves. The peripheral nervous system is divided into two parts which are as follows:

  • Somatic Nervous System
  • Autonomous Nervous System

Importance of Hypothalamus:
Hypothalamus controls the secretions from pituitary gland. Hypothalamus also controls hunger and thirst.
Importance of Pituitary Gland: Pituitary gland secretes growth hormone which controls growth. Secretions of pituitary gland control the secretions from other glands.

Human System Additional Questions Solved

I. Multiple Choice Questions

Question 1:
Which gland of digestive system is inside the alimentary canal?
(a) Salivary gland
(b) Liver
(c) Pancreas
(d) None of these
Answer:
(a) Salivary gland

Question 2:
How many teeth are present in each jaw in a normal adult?
(a) 8
(b) 16
(c) 24
(d) 32
Answer:
(6) 16

Question 3:
Human beings get how many sets of teeth in their lifetime?
(a) One
(b) Two
(c) Four
(d) Many
Answer:
(b) Two

Question 4:
How many incisors are present in each jaw?
(a) One
(b) Two
(c) Four
(d) Eight
Answer:
(c) Four

Question 5:
How many molar teeth are present in each jaw?
(a) One
(b) Two
(c) Four
(d) Six
Answer:
(d) Six

Question 6:
Which part of stomach is connected to oesophagus?
(a) Cardia
(b) Fundus
(c) Pylorus
(d) All of the above
Answer:
(a) Cardia

Question 7:
Which part of stomach is connected to small intestine?
(a) Cardia
(b) Fundus
(c) Pylorus
(d) None of these
Answer:
(c) Pylorus

Question 8:
Digestion takes place in which part of small intestine?
(a) Duodenum
(b) Jejunum
(c) Ileum
(d) All of these
Answer:
(a) Duodenum

Question 9:
Partial digestion of which substance takes place in stomach?
(a) Carbohydrate
(b) Protein
(c) Fat
(d) Mineral
Answer:
(b) Protein

Question 10:
Digestion of protein is completed in which part of alimentary canal?
(a) Mouth
(b) Oesophagus
(c) Stomach
(d) Small intestine
Answer:
(d) Small intestine

Question 11:
Most of the absorption of digested food takes place in which of the following?
(a) Duodenum
(b) Jejunum
(c) Ileum
(d) Colon
Answer:
(b) Jejunum

Question 12:
Bile is produced by which gland?
(a) Salivary gland
(b) Pancreas
(c) Liver
(d) Thyroid gland
Answer:
(c) Liver

Question 13:
Oxygen is mixed with blood in which part of the respiratory system?
(a) Pharynx
(b) Larynx
(c) Trachea
(d) Alveoli
Answer:
(d) Alveoli

Question 14:
Carbon dioxide is removed from blood in which part of the respiratory system?
(a) Pharynx
(b) Larynx
(c) Trachea
(d) Alveoli
Answer:
(d) Alveoli

Question 15:
Dust particles from air are mainly filtered in which part of the respiratory system?
(a) Nasal chamber
(b) Pharynx
(c) Larynx
(d) Trachea
Answer:
(a) Nasal chamber

Question 16:
Which of the following is also known as voice box?
(a) Nasal chamber
(b) Pharynx
(c) Larynx
(d) Trachea
Answer:
(c) Larynx

Question 17:
Which of the following is made up of cartilaginous rings?
(a) Nasal chamber
(b) Pharynx
(c) Larynx
(d) Trachea
Answer:
(d) Trachea

Question 18:
Which of the following is not a part of the upper respiratory system?
(a) Nasal chamber
(b) Pharynx
(c) Larynx
(d) Trachea
Answer:
(d) Trachea

Question 19:
Alveoli are lined with which type of epithelium?
(a) Squamous epithelium
(b) Stratified epithelium
(c) Ciliated epithelium
(d) Glandular epithelium
Answer:
(a) Squamous epithelium

Question 20:
In an adult, blood is produced in which organ?
(a) Lungs
(b) Bone marrow
(c) Spleen
(d) Lymph nodes
Answer:
(b) Bone marrow

Question 21:
In neonates, blood is produced in which organ?
(a) Lungs
(b) Bone marrow
(c) Spleen
(d) Lymph nodes
Answer:
(c) Spleen

Question 22:
Which of the following is not an example of granulocytes?
(a) Neutrophil
(b) Eosinophil
(c) Basophil
(d) Lymphocyte
Answer:
(d) Lymphocyte

Question 23:
WBCs are produced in which organ?
(a) Bone marrow
(b) Spleen
(c) Heart
(d) Lymph nodes
Answer:
(a) Bone marrow

Question 24:
Which of the following is responsible for coagulation of blood?
(a) RBCs
(b) WBCs
(c) Platelets
(d) Plasma
Answer:
(c) Platelets

Question 25:
How many people in the world have Rh positive blood?
(a) 50%
(b) 60%
(c) 70%
(d) 80%
Answer:
(d) 80%

Question 26:
Which is the main excretory organ in human beings?
(a) Kidneys
(b) Skin
(c) Lungs
(d) Heart
Answer:
(a) Kidneys

Question 27:
Which excretory product is removed by lungs?
(a) Urea
(b) Ammonia
(c) Carbon dioxide
(d) Uric acid
Answer:
(c) Carbon dioxide

Question 28:
Excretory waste is filtered from blood in which of the following parts?
(a) Glomerulus
(b) Efferent arteriole
(c) Afferent arteriole
(d) LoopofHenle
Answer:
(a) Glomerulus

Question 29:
What is the age for onset of puberty in girls?
(a) 9-10 years
(b) 12 – 14 years
(c) 16th year
(d) After 18 years
Answer:
(b) 12 – 14 years

Question 30:
Which of the following is the male sex hormone?
(a) Estrogen
(b) Progesterone
(c) Testosterone
(d) Adrenalin
Answer:
(c) Testosterone

Question 31:
Sperms are produced in which organ?
(a) Testis
(b) Seminal vesicle
(c) Vas deferens
(d) Prostate gland
Answer:
(a) Testis

Question 32:
Eggs are produced by which organ?
(a) Ovary
(b) Fallopian tubes
(c) Uterus
(d) Cervix
Answer:
(a) Ovary

Question 33:
What is the gestation period in human beings?
(a) 10 weeks
(b) 20 weeks
(c) 40 weeks
(d) 60 weeks
Answer:
(c) 40 weeks

Question 34:
Fertilisation takes place in which part of the female reproductive system?
(a) Ovary
(b) Fallopian tubes
(c) Uterus
(d) Cervix
Answer:
(b) Fallopian tubes

Question 35:
How many types of neurons are present in the body?
(a) One
(b) Two
(c) Three
(d) Four
Answer:
(b) Two

Question 36:
Involuntary functions are controlled by which part of the brain?
(a) Cerebrum
(b) Cerebellum
(c) Medulla
(d) Pons
Answer:
(c) Medulla

Question 37:
Which is the functional unit of nervous system?
(a) Brain
(b) Spinal cord
(c) Nerves
(d) Neurons
Answer:
(d) Neurons

Question 38:
What is the name of the meeting point of two neurons?
(a) Synapse
(b) Dendrite
(c) Axon
(d) Cyton
Answer:
(a) Synapse

Question 39:
Which hormone is produced by pineal gland?
(a) Gonadotropic hormone
(b) Melatonin
(c) Adrenalin
(d) Thyroxin
Answer:
(b) Melatonin

Question 40:
Which gland is situated above kidneys?
(a) Pituitary gland
(b) Thyroid gland
(c) Adrenal gland
(d) Pancreas
Answer:
(c) Adrenal gland

Human System Very Short Answer Type Questions

Question 1:
What is digestion?
Answer:
The process which converts complex nutrients into simple and absorbable substances is called digestion.

Question 2:
What do you understand by diphyodont?
Answer:
Human beings get two sets of teeth in their lifetime. This phenomenon is called diphyodont.

Question 3:
What is epiglottis?
Answer:
The cartilaginous flap at the entry of windpipe and food pipe is called epiglottis.

Question 4:
Name three parts in which small intestine can be divided.
Answer:
Duodenum, Jejunum and Ileum

Question 5:
What is vermiform appendix?
Answer:
This is a vestigial organ at the junction of small intestine and large intestine.

Question 6:
What is rennin?
Answer:
Rennin is an enzyme to digest milk protein.

Question 7:
Which enzyme is produced in stomach and digests protein?
Answer:
Pepsin

Question 8:
Which acid is produced in stomach?
Answer:
Hydrochloric acid

Question 9:
Large intestine is divided into how many parts?
Answer:
Four

Question 10:
Which gland produces most of the digestive enzymes?
Answer:
Pancreas

Question 11:
Which enzyme is produced by the liver?
Answer:
Bile

Question 12:
Bile is stored in which organ?
Answer:
Gall bladder

Question 13:
Fat is digested by which enzyme?
Answer:
Lipase

Question 14:
After respiration, energy is stored in which form? ‘
Answer:
ATP (Adenosine Triphosphate)

Question 15:
What is the role of mouth in respiration?
Answer:
Mouth plays a secondary role in respiration and facilitates breathing in case the nasal passage is obstructed for some reason.

Question 16:
Which respiratory muscle is present at the floor of thoracic cavity?
Answer:
Diaphragm

Question 17:
Diaphragm is made up of which type of muscle?
Answer:
Skeletal muscle

Question 18:
Which type of blood cells forms major portion of formed elements in blood?
Answer:
Red Blood Cells

Question 19:
Which substance imparts red colour to blood?
Answer:
Haemoglobin

Question 20:
What is the function of macrophages?
Answer:
They eat away antigens.

Question 21:
Which antigen is present in RBCs of blood group AB?
Answer:
Antigen A and antigen B

Question 22:
What is lymph?
Answer:
The interstitial fluid which is drained back into circulation is called interstitial fluid.

Question 23:
What is the name of upper chambers of heart?
Answer:
Atrium or auricle

Question 24:
What is the name of lower chambers of hearth?
Answer:
Ventricle

Question 25:
What is systole?
Answer:
Contraction of heart muscle is called systole.

Question 26:
What is diastole?
Answer:
Relaxation of heart muscle is called diastole.

Question 27:
What is an artery?
Answer:
The blood vessel which carries blood from heart to other organs is called artery. Most of the arteries carry oxygenated blood.

Question 28:
What is a vein?
Answer:
The blood vessel which carries blood from other organs to heart is called vein. Most of the veins carry deoxygenated blood.

Question 29:
What is excretion?
Answer:
Removal of metabolic wastes from body is called excretion.

Question 30:
Give two examples of ammoniotelic animals.
Answer:
Fish, frog

Question 31:
Give two examples of uricotelic animals.
Answer:
Birds, lizards

Question 32:
Which is the functional unit of kidney?
Answer:
Nephron

Question 33:
What is puberty?
Answer:
The onset of changes to lead to sexual maturity is called puberty.

Question 34:
What are secondary sexual characters?
Answer:
Characters which help in easy identification of male and female are called secondary sexual characters.

Question 35:
Which is the primary reproductive organ in males?
Answer:
Testis

Question 36:
Which is the primary reproductive organ in females?
Answer:
Ovary

Question 37:
What is gametogenesis?
Answer:
Formation of gametes (male or female) is called gametogenesis.

Question 38:
What is fertilization?
Answer:
The fusion of male and female gametes is called fertilization.

Question 39:
What is zygote?
Answer:
The end product of fertilization is called zygote.

Question 40:
What is nervous system?
Answer:
The system responsible for controlling all the functions in body is called nervous system.

Question 41:
What is somatic nervous system?
Answer:
The part of the nervous system which controls voluntary actions is called somatic nervous system.

Question 42:
What is autonomous nervous system?
Answer:
The part of the nervous system which controls involuntary actions is called autonomous nervous system.

Question 43:
What is axon?
Answer:
The tail-like structure in a neuron is called axon.

Question 44:
What are the main parts of hind brain?
Answer:
Cerebellum, pond and medulla

Question 45:
What is neuron?
Answer:
The functional unit of nervous system is called neuron. It is unicellular structure.

Question 46:
What is an endocrine gland?
Answer:
A ductless gland is called endocrine gland.

Question 47:
Growth hormone is secreted by which gland?
Answer:
Pituitary gland

Question 48:
What is the location of thyroid gland in our body?
Answer:
Neck

Question 49:
Which hormones are secreted by ovaries?
Answer:
Progesterone and estrogen

Question 50:
Which hormone prepares the body for stress conditions?
Answer:
Adrenaline

Human System Short Answer Type Questions

Question 1:
What is digestion? What is the need for digestion?
Answer:
Conversion of complex nutrients into simple substances to make them soluble and absorbable is called digestion. The components of food are complex substances and cannot be utilized by the body. They need to be changed into simple substances so that the body can utilize them. Hence, there is the need for digestion.

Question 2:
What are the main parts of alimentary canal?
Answer:
Main parts of alimentary canal are mouth, pharynx, oesophagus, stomach, small intestine, large intestine and rectum.

Question 3:
Name different types of salivary gland.
Answer:
Following are the three types of salivary gland:
Parotid gland
Sub-mandibular gland
Sublingual gland

Question 4:
Give a brief description of three parts of stomach.
Answer:
Stomach can be divided into three parts which are as follows:

  • Cardia: This part is at the left and is connected to the oesophagus.
  • Fundus: This part lies between cardia and pylorus.
  • Pylorus: This part opens into small intestine.

Question 5:
Briefly explain the main parts of small intestine.
Answer:
The small intestine can be divided into three portions, viz. duodenum, jejunum and ileum.

  • Duodenum: This is the anterior- most portion of small intestine and is connected to pylorus. All the digestive juices come into duodenum and digestion of food takes place here.
  • Jejunum: This is the middle portion of small intestine. Absorption of most of the digested food takes place in jejunum. Absorption is carried by specialized cells which are called enterocytes.
  •  Ileum: This is the last portion of small intestine and is connected to large intestine. Some of the substances which are not absorbed by jejunum are absorbed in this portion, e.g. bile salts and vitamins.

Question 6:
Briefly explain the main parts in which colon of large intestine can be divided.
Answer:
The colon can be divided into four parts, which are as follows:

  • Ascending Colon: This part is about 15 cm long and goes upwards from near appendix.
  • Transverse Colon: This part is about 50 cm long and is almost horizontal.
  • Descending Colon: This part is about 25 cm long and goes downwards.
  • Sigmoid Colon: This part is about 40 cm long and is somewhat S-shaped.

Question 7:
Right a short note on liver.
Answer:
Liver is the largest gland in the human body. It is situated below the diaphragm and its major portion is towards right side. Liver is composed of about 100,000 hexagonal functional units which are called liver lobules. Liver produces bile which goes to the gall bladder through hepatic duct system. From gall bladder, bile goes to the small intestine through hepatopancreatic duct.

Question 8:
Explain the digestion of food in mouth.
Answer:
Mastication breaks the food into smaller particles. This helps in properly mixing the saliva to the food. The mucus in saliva helps in food particles coalescing together. About 30% of starch is converted into maltose in the buccal cavity.

Question 9:
Explain the digestion of food in stomach.
Answer:
Stomach secretes three digestive juices, viz. mucus, proenzyme pepsinogen and hydrochloric acid. Mucus is secreted by mucus membrane, and hydrochloric acid is secreted by oxyntic cells. Hydrochloric acid kills any germs in food and makes the medium in stomach acidic. Acidic medium is necessary for working of gastric enzyme. Pepsinogen changes to pepsin which digests protein into peptide. Rennin is secreted in small children and helps in digestion of milk protein.

Question 10:
Write a short note on exchange of gases in lungs.
Answer:
This happens in alveoli. The pressure difference between air in alveoli and gases in capillaries facilitates removal of carbon dioxide from blood and addition of oxygen to blood.

Question 11:
Write a short note on RBCs.
Answer:
RBCs comprise 99% of blood cells. RBCs contain a protein called haemoglobin which imparts red colour to them. They lack nucleus. The life of RBCs is 120 days.

Question 12:
What do you understand by types of blood?
Answer:
Based on the presence or absence of a special antigen A or B, there are four types of blood, viz. A, B, AB and O. Blood group A has antigen A, blood group B has antigen B, blood group AB has both antigens and blood group O has none. RBCs also contain another antigen which is called Rh factor. Blood with Rh factor is called Rh positive, while one without Rh factor is called Rh negative. About 80% people in the world have Rh positive blood.

Question 13:
What is double circulation? What is the benefit of double circulation?
Answer:
In humans, blood passes through the heart twice during a cardiac cycle. Once, the deoxygenated blood passes through the heart and then the oxygenated blood passes through the hearth. This is called double circulation. In this case, deoxygenated blood is completely separated from oxygenated blood. Hence, this is a highly efficient method of blood circulation. Animals which show double circulation are more active, more energetic and are warm blooded animals. Double circulation is present in mammals and birds.

Question 14:
What is excretion? What is the need for excretion?
Answer:
Removal of metabolic wastes from body is called excretion. Many waste products are created in the body during various metabolic processes. These substances would prove harmful and even toxic if they are not removed from the body on time. Hence, there is a need for excretion.

Question 15:
Explain the structure of a nephron.
Answer:
A nephron is composed of the filtering unit and highly convoluted ducts. The filtering unit is called glomerular apparatus. It is composed of a cup-shaped structure called Bowman’s capsule. There is a tuft of capillaries inside Bowman’s capsule. This tuft of capillaries is called glomerulus. The renal artery sends blood to glomerulus and renal vein collects blood from glomerulus. The glomerulus is followed by highly convoluted tubule which is followed by collecting duct.

Question 16:
What are the changes which take place in adolescent boys?
Answer:
Following changes take place in adolescent boys:

  • Shoulders become broad.
  • Body becomes muscular.
  • There is a sudden increase in height.
  • Voice becomes deeper.
  • Facial hairs appear.
  • Hairs grow under armpit and in pubic area.

Question 17:
Make a well labelled diagram of male reproductive system,

Answer:

Question 18:
Make a well labelled diagram of female reproductive system.

Answer:

Question 19:
Write a short note on cleavage and implantation.
Answer:
After fertilization, the zygote undergoes many rounds of mitosis. This results in a multicellular structure which appears like a ball. This process is called cleavage and the structure is called blastula. After that, the embryo moves down the uterus and gets implanted in endometrium. This is called implantation. Implantation marks the beginning of pregnancy.

Question 20:
Write a short note on midbrain.
Answer:
This is a very small part of brain. Midbrain lies below the forebrain and somewhere between forebrain and hindbrain. The midbrain is composed of four lobes which are called corora quadrigemina. The upper lobes are responsible for sense of vision while lower lobes are responsible for sense of hearing.

Question 21:
Write a short note on thyroxin.
Answer:
Thyroxin is a hormone which is produced by thyroid gland. Iodine is the main constituent of this hormone. This hormone plays many important functions. It helps in production of red blood cells. It controls the metabolism of carbohydrate, protein and fat. Iodine deficiency reduces the production of thyroxin which leads to a disease called goiter.

Human System Long Answer Type Questions

Question 1:
Describe the structure and functioning of nephrons.

Answer:
Structure of nephrons: It consists of a Bowman’s capsule in which glomerulus is present (cluster of capillaries). The afferent artery brings the impure blood to nephron. The cup shaped structure (Bowman’s capsule) form a tubular part of nephron which leads to collecting duct.

Working of Nephron

  1.  Filtration: The renal artery or afferent artery is wider and slowly it becomes a narrow tube in the glomerulus. Due to difference in the width, pressure difference is caused and water with dissolved impurities are squeezed out from the tube. It is collected in the Bowman’s capsule which is cup-like structure and passes into the tube.
  2. Reabsorption: The above filtrate passes through the tubule where the major amount of water, glucose, amino acids are selectively reabsorbed by the capillaries which are surrounding the tubule.
  3.  Urine formation: The water and impurities which is not reabsorbed is sent to a collecting duct. This filtrate contains more of dissolved nitrogenous wastes i.e. urea and hence it is termed as urine. From here the urine enters the ureter and is collected in urinary bladder.

Question 2:
Describe the digestive system.
Answer:
The different parts of the digestive system are as follows:

  1. Buccal cavity opens outside through the mouth. It has the tongue, teeth and the opening of the salivary gland.
  2. Buccal cavity leads to oesophagus.
  3. The oesophagus opens into the stomach. The wall of the stomach contains gastric glands.
  4. The stomach opens into the duodenum. This opening is regulated by a sphincter muscle which releases small amount of food at a time.
  5. The duodenum receives the secretions of the liver and the pancreas.
  6. From the duodenum, the food passes into the small intestine. The inner wall of the small intestine has a number of finger like projections called villi. The villi increases the surface area and are richly supplied with blood vessels.
  7. The small intestine opens into the large intestine.
  8. The terminal portion of the large intestine is called the rectum that opens out through the anus.

Question 3:
Explain breathing mechanism.
Answer:
The cartilaginous diaphragm when contracts, increases the surface area for lungs which spreads, thereby, reducing the air pressure in it. The pressure of air at the nostrils is more and hence the air flows from higher pressure area to lower pressure area i.e. lungs. This is called inhalation. When the diaphragm relaxes, it pushes the lungs thereby increasing the pressure on them and the surface area reduces and hence the pressure of air in the lungs is more which is forced/given out from the nostrils. This is called exhalation.

Question 4:
Differentiate between arteries and veins.
Answer:

Arteries Veins
1. Arteries are thick walled. Veins are thin walled.
2. They are deep seated. They are superficial.
3. They carry blood away from heart. They carry blood to the heart.
4. The arteries carry oxygenated blood. The veins carry deoxygenated blood.
5. No valves are present in it. Valves are present in it.

Question 5:
(a) Name all the digestive enzymes 1 complex carbohydrates into glucose present in our digestive system. and fats into fatty acid and glycerol.
(b) Explain the process of digestion of carbohydrates fats and proteins.
(c) Why do people complain of acidity problems on consuming too much of fats and proteins?
Answer:
(a) The digestive enzymes present in our system are: Salivary amylase, pepsin, trypsin, lipase, pancreatic amylase.
(b) Carbohydrates: It is acted upon by salivary amylase in mouth which convert complex insoluble starch into simpler sugar. The food with carbohydrate if not digested in mouth then it is digested by amylase from pancreas to form glucose.
Fats: Bile from liver breaks the big globules of fats into smaller ones and is acted upon by lipase from pancreas which digest fats into fatty acids. Proteins: Proteins are first digested by pepsin in stomach to form peptones. This is further digested by trypsin from pancreas to form amino acids.
The enzymes present in small intestine finally convert protein to amino acids, complex carbohydrates into glucose and fats into fatty acid and glycerol.
(c) Fats and proteins containing/ rich food on digestion releases fatty acids and amino acids respectively. Hence large amount of acid is formed in the body which leads to acidity problems.

Question 6:
(a) Draw a labelled sectional view of human heart.
(b) State the functions of the following components of transport system:
(i) Blood (ii) Lymph
Answer:
(a) Diagram of human heart.

(b) (i) Functions of Blood

  1. It maintains body temperature.
  2. Transports material like food, water and amino acids.
  3. Maintains immunity, fights with the germs.
  4. Helps in clotting in case of injury
  5.  It transports oxygen to maintain energy levels.

(ii) Functions of Lymph

  1.  It transports fat.
  2.  It carries digested and absorbed fat from intestine.
  3.  It drains excess fluid from extracellular space back into the blood.

Question 7:
(a) Draw a sectional view of human heart and label on it aorta, pulmonary vein, vena cava, left ventricle.
(b) Why is double circulation of blood necessary in human being? [AI CBSE 2009]
Answer:

(b) The blood passes through the heart twice. Right side of the heart receives deoxygenated blood which is circulated to lungs for purification. At the same time the left side of the heart receives oxygenated blood which is circulated to the body. This is called double circulation.

Question 8:
What are the different parts of the brain? Give functions of each part.
Answer:
The brain is divided into three regions: fore brain, mid brain and hind brain.

Fore brain:

  1. The fore brain includes the cerebrum and the olfactory lobes.
  2.  The cerebrum is the largest part of the brain and consists of two cerebral hemispheres. It has sensory areas where information is received from sense organs, Similarly there are motor areas from where impulses are sent to effector organs.
  3.  In the cerebrum specific regions for each kind of stimulus and its response are located. E.g., there are specialized regions for hearing, smell and sight.

Mid brain:

  1. It is made up of thalamus and hypothalamus.
  2. It connects the fore brain to the hind brain.

Hind brain:
It consists of cerebellum, pons and medulla.

  1. Cerebellum controls coordination, adjustment of movement and posture of our body.
  2. Pons regulates respiration.
  3. Medulla is the centre of involuntary actions like salivation, vomiting, sneezing coughing etc.

Question 9:
Name the secretions of the following glands and give their function: pituitary, testis and ovary.
Answer:

  • Pituitary: It secretes growth hormone which regulates growth and development of the body. Excessive secretion causes
  • gigantism and decreased secretion causes dwarfism.
  • Testis: Secretes testosterone which regulates male accessory sex organ and secondary sexual characters.
  • Ovary: Secretes oestrogen which regulates female accessory sex organs and secondary sexual characters in females.

Question 10 :
Differentiate between the following:
(a) Spinal nerve and cranial nerve
(b) Dendrite and axon
(c) Central nervous system and peripheral nervous system
Answer:
(a)

Spinal nerve Cranial nerve
  1. It arises from spinal cord.
  2. Their functions are concerned mainly with the acitivities associated with head and neck.
  1. It arises from brain.
  2. Their functions are associated with all the body parts, below the neck.

(b)

Dendrite Axon
  1. They are the short branched parts, arises from the cell body.
  2. They receive messages from other cells.
  1. It is a long unbranched part that comes from the cell body.
  2. They passes messages away from the cell body to other neurons, muscles and glands.

(c)

Central nervous system Peripheral nervous system
  1. It consists of brain and spinal cord.
  2. It contains centres for controlling various activities of the body.
  1. It consists of cranial nerves, spinal nerves and visceral nerve
  2. No such centre is present for controlling, as nerves only transmit the impulse.